Arthroplasty sizing gauge

ABSTRACT

A gauge ( 10 ) for measuring bone contour ( 12 ) of a bone( 4 ) for use in joint arthroplasty is provided. The gauge ( 10 ) includes a body ( 14 ) and a probe ( 16 ). The body ( 14 ) has a body contact portion of the body ( 14 ) for contact with the bone ( 4 ). The probe ( 16 ) is movably positional with respect to the body ( 14 ). The probe ( 16 ) includes a probe contact portion of the probe ( 16 ) for contact with the bone ( 4 ). The relative position of the probe ( 16 ) with respect to the body ( 14 ) is indicative of the bone contour ( 12 ) of the bone ( 4 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Cross reference is made to the following applications: DEP 756entitled “ARTICULATING SURFACE REPLACEMENT PROSTHESIS”, DEP 789 entitled“MODULAR ARTICULATING SURFACE REPLACEMENT PROSTHESIS”, DEP 5041 entitled“ARTHROPLASTY INSTRUMENT AND ASSOCIATED METHOD”, DEP 5042 entitled“EXTENDED ARTICULATION ORTHOPAEDIC IMPLANT AND ASSOCIATED METHOD” andDEP 5052 entitled “PROSTHETIC IMPLANT, TRIAL AND ASSOCIATED METHOD”filed concurrently herewith which are incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates generally to the field oforthopaedics, and more particularly, to an implant for use inarthroplasty.

BACKGROUND OF THE INVENTION

[0003] The invention relates to implantable articles and methods forimplanting such articles. More particularly, the invention relates to abone prosthesis instrument and a method for using the same.

[0004] There are known to exist many designs for and methods forimplanting implantable articles, such as bone prostheses. Such boneprostheses include components of artificial joints, such as elbows,hips, knees and shoulders. An important consideration in the design andimplanting of virtually any implantable bone prosthesis is that the bonehave adequate fixation when implanted within the body.

[0005] Earlier designs of implantable articles relied upon the use ofcement, such as polymethylmethacrylate (PMMA) to anchor the implant. Theuse of such implants can have some advantages, such as providingfixation that does not develop free play or does not lead to erosion ofjoining faces postoperatively. However, the current trend is to use thecements to a lesser extent because of their tendency to lose adhesiveproperties over time and the possibility that cement contributes to weardebris within a joint.

[0006] Recently, implantable bone prostheses have been designed suchthat they encourage the growth of hard bone tissue around the implant.Such implants are often implanted without cement and the bone growsaround surface irregularities, for example, porous structures on theimplant.

[0007] One such implantable prosthesis is a shoulder prosthesis. Duringthe lifetime of a patient, it may be necessary to replace the naturalhumeral head and associated glenoid cavity with a prosthesis. Such ashoulder replacement procedure may be necessary to be performed on apatient as a result of, for example, disease or trauma, for example,disease from osteoarthritis or rheumatoid arthritis.

[0008] Most shoulder replacement surgeries today involve theimplantation of a total shoulder prosthesis. In a total shoulderreplacement procedure, a humeral component having a head portion isutilized to replace the natural head portion of the upper arm bone orhumerus. The humeral component typically has an elongated intramedullarystem which is utilized to secure the humeral component to the patient'shumerus. In such a total shoulder replacement procedure, the naturalglenoid surface of the scapula is restructured or otherwise replacedwith a glenoid component that provides a bearing surface for the headportion of the humeral component.

[0009] With the average age of patients requiring shoulder arthroplastydecreasing, orthopaedic implant manufacturers are developing“bone-sparing” implants for the initial treatment of degenerativearthritis. While bone-sparing implants for the treatment of hip and kneearthroplasty are becoming quite common, bone-sparing shoulderarthroplasty techniques and prostheses are also being developed.

[0010] Shoulder surface replacement prostheses are being developed toreplace the articulating surface of the proximal humerus with a minimalbone resection and minimal disruption of the metaphysis and thediaphysis. Current designs use a semi-spherical articular dome with asmall stem for rotational stability. The under surface of the articularhead is also semi-spherical and meets with a spherically machinedhumeral head.

[0011] Typically, however, arthritis of the gleno-humeral joint causesflattening of the humeral head with a large medial osteophyte. The flathumeral head can cause voids in the bone under the prosthesis resultingin limited contact between the prosthesis and the resected bone and maylimit the load transfer capability between the prosthesis and thehumerus.

[0012] Referring now to FIG. 2, a healthy long bone or, in the form of,for example, a humerus 1 is shown. The humerus 1 includes a head 2 onthe proximal end of the humerus 1. The head 2 of a healthy humerus hasan arcuate outer periphery. The arcuate outer periphery is generallyhemispherical and meets with a concave glenoid cavity 3.

[0013] Referring now to FIG. 3, a diseased humerus 4 is shown. Thediseased humerus 4 includes a head 5. The head 5 is flattened as shownin FIG. 3. The humerus 4 also has developed a large medial osteophyte 7.

[0014] Referring now to FIG. 4, a prior art prosthesis 8 is shown inposition on the head 5 of diseased humerus 4. The head 5 includes aflattened humeral head area or bony defect 9 that leads to a void 6between the prosthesis 8 and the bony defect 9.

[0015] Great variations in the size of a patient's humerus and thehumeral head of that humerus, as well as variations in the progress ofthe arthritis or other disease that leads to the flattening of thehumeral head results in a large variation in the amount of void in thebone under the prosthesis. Determining the amount of void in the humeralhead is, therefore, important but yet, difficult to determine.Radiographic techniques including x-rays can be used to determine theshape of a long bone, for example, a humerus. Such x-rays, however, onlyportray the broad outline of the humerus and may not accurately show theshape of the defect.

[0016] There is a need, therefore, for a better method of determiningthe size of the void under the bone of a prosthesis caused by theflattening of the humeral head from osteoarthritis or other degenerativebone diseases.

SUMMARY OF THE INVENTION

[0017] The present invention includes a proposed instrument that may beused to size the humeral head for a surface replacement prosthesis. Theinstrument may also be used to determine the appropriate amount ofresection of the humeral head. The device further can be used todetermine the required thickness of augmentation spacers that may beused with the surface replacement prosthesis for replacing the missingbone. The instrument of the present invention may also be used todetermine the placement of a guide rod to align cutting tools used forpreparing the humeral head for the fitting of a humeral prosthesis.

[0018] According to one embodiment of the present invention, a gauge formeasuring bone contour of a bone for use in joint arthroplasty isprovided. The gauge includes a body and a probe. The body has a bodycontact portion of the body for contact with the bone. The probe ismovably positional with respect to the body. The probe includes a probecontact portion for contact with the bone. The relative position of theprobe with respect to the body is indicative of the contour of the bone.

[0019] According to another embodiment of the present invention, a kitfor use in selecting one of a plurality of joint implants for use injoint arthroplasty on a bone is provided. The kit has a first gauge anda second gauge.

[0020] The first gauge includes a first gauge body having a portion ofthe first gauge body for contact with the bone and a first gauge probe.The first gauge probe is movably positional with respect to the firstgauge body. The first gauge probe has a portion for contact with thebone. The relative position of the first gauge probe with respect to thefirst gauge body is indicative of the contour of the bone. The secondgauge includes a second gauge body having a portion of the second gaugebody for contact with the bone and a second gauge probe. The secondgauge probe is movably positional with respect to the second gauge body.The second gauge probe has a portion for contact with the bone. Therelative position of the second gauge probe with respect to the secondgauge body is indicative of the contour of the bone.

[0021] According to yet another embodiment of the present invention, akit for use in performing joint arthroplasty on a bone is provided. Thekit includes a first implant having a first implant surface for contactwith the bone. The kit also includes a second implant having a secondimplant surface for contact with the bone. The second implant has atleast one dimension different from the corresponding dimension of thefirst implant. The kit further includes a first gauge. The first gaugehas a first gauge body having a contact portion of the first gauge bodyfor contact with the bone. The first gauge contact portion is shaped tocorrespond to the first contact surface of the first implant. The kitalso includes a second gauge. The second gauge has a second gauge bodyhaving a second gauge contact portion of the second gauge body forcontact with the bone. The second gauge contact portion is shaped tocorrespond to the second implant contact surface of the second implant.The first gauge contact portion has at least one dimension that isdifferent from the corresponding dimension of the second gauge contactportion.

[0022] According to a further embodiment of the present invention, amethod for providing joint arthroplasty is provided. The method includesthe steps of providing a gauge for making a measurement of the contourof a long bone, making a measurement of the contour of a long bone withthe gauge, providing a plurality of joint prostheses, selecting one ofthe plurality of joint prostheses based upon the measurement of thecontour, and implanting the selected one prosthesis onto the long bone.

[0023] The technical advantages of the present invention include anability to accurately measure the void in the bone of a flattenedhumerus under the prosthesis. For example, according to one aspect ofthe present invention, the gauge of the present invention includes abody, which has a contact face with a shape corresponding to that of theinterior periphery of the prosthesis to be implanted as well as a probeextending from that body. By measuring the location of the proberelative to the body, an accurate measurement can be made of the void inthe natural humerus. Thus, the present invention provides for anaccurate measurement of the void of the flattened humeral head.

[0024] Another technical advantage of the present invention is theability to size the humeral head for a surface replacement prosthesis.For example, according to one aspect of the present invention, the gaugeof the present invention includes a body which has an internal shapesimilar to that of the internal shape of the prosthesis, as well as awindow in the body of the gauge such that the gauge can be used todetermine the appropriateness of a particular sized surface replacementprosthesis. The gauge can be used to obtain a physical feel of the fitof the prosthesis as well as a visual check of the appropriateness ofthe prosthesis by viewing a bone through the slots in the gauge. Thus,the present invention provides for a tool to size the humeral head for asurface replacement prosthesis.

[0025] The technical advantages of the present invention furtherincludes an apparatus and method for determining the required thicknessof augmentation spacers for filling the missing bone. For example,according to one aspect of the present invention, the gauge of thepresent invention includes a body having an internal shape similar tothat of the internal shape of the prosthesis, as well as, a probeextending from the inside of the body to contact the flattened humeralhead. The probe can be used to determine the required thickness of theaugmentation spacers by measuring the position of the probe when itcontacts the flattened humerus. Thus, the present invention provides fora method of determining the required thickness of the augmentationspacers.

[0026] The technical advantages of the present invention furtherincludes an ability to use the gauge to determine the placement of aguide rod in the bone. The rod can be used to guide an instrument forfitting a prosthesis. For example, according to one aspect of thepresent invention, the gauge of the present invention includes a bodywhich has an internal periphery similar to that of the prosthesis to beimplanted, plus a central opening which slotably fits with a guide rod.The rod can be removed and a self-drilling rod can be placed in the boneto guide an instrument, for example, a reamer. Thus, the presentinvention provides for a tool to assist in the placement of the guiderod for other machining operations for fitting a prosthesis.

[0027] Other technical advantages of the present invention will bereadily apparent to one skilled in the art from the following figures,descriptions and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] For a more complete understanding of the present invention andthe advantages thereof, reference is now made to the followingdescription taken in connection with the accompanying drawings, inwhich:

[0029]FIG. 1 is a plan view partially in cross section of a gaugeaccording to the present invention for determining the appropriatespacer for a surface replacement prosthesis for use on a diseasedhumerus;

[0030]FIG. 2 is a plan view of a healthy humerus;

[0031]FIG. 3 is a plan view of a diseased humerus;

[0032]FIG. 4 is a plan view partially in cross section of a prior arthumeral prosthesis;

[0033]FIG. 5 is a plan view of a resected humerus showing the resectedportion in phantom;

[0034]FIG. 6 is a plan view partially in cross section of a resectedhumerus with a cavity prepared for a prosthesis gauge;

[0035]FIG. 7 is an auxiliary view of resected humerus with a cavity ofFIG. 6;

[0036]FIG. 8 is a plan view partially in cross section of anotherembodiment including an offset handle of a gauge according to thepresent invention for determining the appropriate spacer for a surfacereplacement prosthesis for use on a diseased humerus;

[0037]FIG. 9 is a plan view of the housing of the gauge of FIG. 1;

[0038]FIG. 10 is a plan view of the probe for use in the gauge of FIG.1;

[0039]FIG. 11 is a plan view partially in cross section of a surfacereplacement prosthesis with a screwed-on spacer for which the gauge ofthe present invention may be utilized to determine the appropriate sizeof the spacer;

[0040]FIG. 12 is a plan view partially in cross section of anotherembodiment of a surface replacement prosthesis with a tapered fit spacerfor which the gauge of the present invention may be utilized todetermine the appropriate size of the spacer;

[0041]FIG. 13 is a plan view partially in cross section of anotherembodiment of a surface replacement prosthesis with a bolted-on spacerfor which the gauge of the present invention may be utilized todetermine the appropriate size of the spacer;

[0042]FIG. 14 is a plan view partially in cross section of anotherembodiment of a surface replacement prosthesis with a bolted-on spacerand stem for which the gauge of the present invention may be utilized todetermine the appropriate size of the spacer;

[0043]FIG. 15 is a plan view partially in cross section of anotherembodiment of a surface replacement prosthesis with a screwed-on spacerwith a portion of the prosthesis having porous coating for which thegauge of the present invention may be utilized to determine theappropriate size of the spacer;

[0044]FIG. 16 is a plan view partially in cross section of anotherembodiment of a surface replacement prosthesis with a three-piece cup,spacer and stem assembly with porous coating for which the gauge of thepresent invention may be utilized to determine the appropriate size ofthe spacer;

[0045]FIG. 17 is a perspective view of a trial for use with the surfacereplacement prosthesis for which the gauge of the present invention maybe utilized to determine the appropriate size of the spacer;

[0046]FIG. 18 is a plan view of a set of surgical instruments that maybe used in performing shoulder arthroplasty according to a furtherembodiment of the present invention;

[0047]FIG. 19 is a perspective view of a reamer that may be used toprepare the humerus for the surface replacement prosthesis for which thegauge of the present invention may be utilized to determine theappropriate size of the spacer;

[0048]FIG. 20 is an exploded plan view partially in cross section ofanother embodiment of a surface replacement prosthesis with athree-piece cup, spacer and stem for which the gauge of the presentinvention may be utilized to determine the appropriate size of thespacer;

[0049]FIG. 21 is an exploded plan view partially in cross section ofanother embodiment of a surface replacement prosthesis kit with athree-piece cup, a set of two spacers and a stem for which the gauge ofthe present invention may be utilized to determine the appropriate sizeof the spacer;

[0050]FIG. 22 is a plan view of a kit including a plurality of gaugesfor use in performing shoulder arthroplasty according to a furtherembodiment of the present invention;

[0051]FIG. 23 is a plan view of a kit including a plurality ofprostheses and gauges for use in performing shoulder arthroplastyaccording to a further embodiment of the present invention;

[0052]FIG. 24 is a process flow chart for a method of performingshoulder arthroplasty according to another embodiment of the presentinvention; and

[0053]FIG. 25 is a plan view partially in cross section of a gauge foruse with a femur according to another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0054] Embodiments of the present invention and the advantages thereofare best understood by referring to the following descriptions anddrawings, wherein like numerals are used for like and correspondingparts of the drawings.

[0055] According to the present invention and referring to FIG. 1, gauge10 is shown. The gauge 10 is used for measuring bone contour 12 of thebone 4, for example, a humerus, for use in joint arthroplasty. The gauge10 includes a body 14 and a probe 16. The body 14 has a portion 18 ofthe body 14 for contact with the bone 4. The probe 16 is movablypositional with respect to the body 14. The probe 16 includes a contactportion 21 of the probe 16 for contact with the bone 4. The relativeposition of the probe 16 with respect to the body 14 is indicative ofthe bone contour 12 of the bone 4.

[0056] The gauge 10 may, as shown in FIG. 1, be such that at least aportion of the portion 18 for contact with the bone 4 includes acontoured portion with a periphery 20 similar to the internal peripheryof the prosthesis to be implanted.

[0057] The gauge 10 of FIG. 1 may, for example, provide that at least aportion of the body 14 includes a concave surface. As shown in FIG. 1,the internal periphery 20 may be concave. In fact, as shown in FIG. 1,the internal periphery 20 may be hemispherical.

[0058] Referring now to FIG. 9, the body 14 of the gauge 10 is shown ingreater detail. The body 14 includes a generally hollow cylindricalportion 22 as well as a hollow hemispherical portion 24. As shown inFIG. 9, a radius R1 extending from origin 26 may define the innerperiphery 20 of the hemispherical portion 24.

[0059] Referring again to FIG. 1, while the probe 16 may be movablypositioned with respect to the body 14 in any suitable fashion, as shownin FIG. 1, the body 14 defines a longitudinal opening 28 therein. Asshown in FIG. 1, the probe 16 may be slidably fitted into the opening28.

[0060] As shown in FIG. 1, the probe 16 may include a generallycylindrical portion 30 having a diameter, for example, DP. Thelongitudinal opening 28 may be generally cylindrical defined by adiameter DO. The diameter DP is preferably slightly smaller than thediameter DO to permit the sliding motion of the probe 16 in thedirection of arrows 32.

[0061] The gauge of the present invention may, as shown in FIG. 1,include indicia 34 located on the body 14 or the probe 16. It should beappreciated that the indicia 34 may be located on both the probe 16 andthe body 14. The indicia 34 correspond to the relative position of theprobe 16 with respect to the body 14.

[0062] As shown in FIG. 1, the body 14 of the gauge 10 may include abody indicia opening 36 for assisting in viewing the indicia 34. Theindicia 34 may have any suitable form and may, for example, includemarks 38 or characters 40 in the form of, for example, numerals orletters. The marks 38 and the characters 40 may be located on either thebody 14 or the probe 16.

[0063] As shown in FIG. 1, the gauge 10 includes characters 40 locatedon the probe 16, and a plurality of marks 38 equally spacedlongitudinally along the probe 16, as well as a solitary mark 38 locatedon the body 14. The alignment of the solitary mark on the body with thecorresponding mark 38 on the probe corresponds to the relative positionof bone contact surface 42 of the probe contact portion 21 of the probe16. As shown in FIG. 1, the probe 16 adjacent the bone contact surface42 may be substantially wider than cylindrical position 30 of the probe16 in order to obtain a more representative indication of the bonecontour 12.

[0064] As shown in FIG. 1, the body 14 of the gauge 10 may include aviewing opening 44 for visually sighting the condition of the bonecontour 12, while positioning the gauge 10 with respect to the bonecontour 12. The viewing opening 44 may have any shape but may, as shownin FIG. 1, be generally elongate and arcuate corresponding to the bonecontour 12.

[0065] Referring again to FIG. 9, the gauge 10 may provide an additionalfunction to that already mentioned by being able to be used to assist inpreparing a locating hole 46 in the head 5 of the humerus 4 (see FIG.6). The locating hole 46 may be used to guide tools used to prepare thehead 5 of the humerus 4 for an appropriate prosthesis. When utilizingthe gauge 10 to prepare the locating hole 46, the body 14 of the gauge10 is brought in a position relative to the head 5 of the humerus 4 bysight as it is located along the bone contour 12 in the direction ofarrows 48. Using the viewing window 44, as well as, the cylindricalportion 22 of the body 14 as guides to determine the proper orientationof the locating hole 46. A drill 50 in the form of, for example, astandard spiral point drill having a size compatible for a sliding fitwith opening 28 may be inserted through opening 28 and used to form thelocating hole 46 after the probe 16 has been removed from the body 14 ofthe gauge 10.

[0066] Referring now to FIG. 10, the probe 16 is shown in greaterdetail. As shown in FIG. 10, the indicia 34 include marks 38 that areequally spaced longitudinally along the cylindrical portion 30 of theprobe 16. Characters 40 in the form of, for example, numbers are spacedadjacent to some of the marks 38. The characters 40 may be used toindicate a relative position of the bone contact surface 42 of the probe16 with respect to the body 14 or may be used to represent a particularsize of a prosthesis which would be appropriate for that particular bonecontour, or to select a particular cutting tool that should be used, orto determine a setting on a cutting tool that should be used tocorrespond to that particular reading.

[0067] To assure that the gauge 10 is properly positioned with respectto the bone contour 12, the probe 16 may include a pilot 52 which may befitted into the locating hole 46.

[0068] Referring now to FIG. 8, an alternate embodiment of the presentinvention is shown as gauge 110. The gauge 110 is similar to the gauge10 of FIG. 1, except that the gauge 110 is designed to assist in theease of viewing the position of the gauge with respect to the bonecontour 12. When utilizing the gauge 10 of FIG. 1, the cylindricalportion 22 of the body 14 serves as the handle for the gauge 10. Whengripping the gauge 10 by the handle 22, the viewing window 44 isobstructed by the person's hand. Thus, when utilizing the gauge 10 theviewing of the window 44 to assist in determining the proper position ofthe head 5 with respect to the gauge may be more difficult. Therefore,gauge 110 is designed to alleviate the viewing window problem.

[0069] As shown in FIG. 8, the gauge 110 includes a body 114 having acylindrical portion 122 similar to the cylindrical portion 22 of thegauge 10 of FIG. 1. The body 114 further includes a hollow hemisphericalportion 124 similar to the portion 24 of the gauge 10. The cylindricalportion 122 includes a longitudinal cylindrical opening 128 as well asan indicia opening 136. The hemispherical portion 124 includes a viewingwindow 144 to view the head 5 in assisting the proper positioning of thegauge 110.

[0070] As shown in FIG. 8, the gauge 110 includes a separate handle 154separate from the cylindrical body 122. The handle 154 is utilized forholding the gauge 110 in position with respect to the head 5. It can beseen that the handle 154 is preferably opposed to the viewing window 144so that the head 5 may be clearly viewed through the viewing window 144while the gauge 110 is being held by the handle 154.

[0071] Referring now to FIGS. 5, 6 and 7, a long bone in the form of ahumerus 4 is shown in varying stages of preparation for receiving aprosthesis utilizing the gauge of the present invention, as well as thesurgical method of the present invention.

[0072] Referring to FIG. 5, the humerus 4 is shown with a portion of theflattened head 5 resected. The head 5 is resected along resection line54 providing a resected surface 56. The surface 56 may be resected byany suitable method, for example, a reamer, a mill end cutter, a saw, oran osteotome. The location of the resection line 54 may be determined byutilizing the gauge 10 of FIG. 4. The indicia 34 on the gauge 10 of FIG.1 may be utilized to determine the position of the resection line 54 andthe proper depth of the surface 56.

[0073] Referring now to FIGS. 6 and 7, the long bone in the form ofhumerus 4 is shown with the head 5 being prepared for a prosthesis usedin conjunction with the gauge and surgical procedure of the presentinvention. The prosthesis for use with the gauge and surgical method ofthe present invention may include a stem (not shown) for securing theprosthesis to the humerus 4.

[0074] To accommodate the stem, a tapered securing or mounting hole 58may be prepared in the humerus 4. The mounting hole 58 may have agenerally tapered cylindrical shape having a longitudinal centerline 60perpendicular to the surface 56.

[0075] Any suitable tool may be utilized to form the mounting hole 58.For example, the mounting hole 58 may be machined into the humerus 4 bythe use of a reamer. The mounting hole 58 may be positioned a depth CMfrom the resection line 54. The dimension CM may be establishedutilizing the gauge 10 of FIG. 1. The gauge 10 of FIG. 1 may establishthe proper prosthesis for a given bone contour and the dimension CM maycorrespond to that recommended for that particular prosthesis.

[0076] The preparation of the head 5 of the humerus 4 may furtherinclude an arcuate support surface 64 formed adjacent the head 5. Thearcuate surface 64 preferably conforms to that of the prosthesis and isgenerally arcuate and may be generally hemispherical. The arcuatesurface 64 may be applied into the humerus 4 in any suitable fashion.For example, the arcuate surface 64 may be machined by a grater-typereamer.

[0077] The position of the arcuate surface 64 may be determined by, forexample, a depth AH at a diameter AD. The dimensions AD and AH may bedetermined with the assistance of the gauge 10 of FIG. 1. For example,the gauge 10 may be utilized to determine the proper prosthesis and thedimensions AH and AD may be determined upon that particular prosthesis.

[0078] It can be seen that the gauge 10 of FIG. 1, as well as the gauge110 of FIG. 8 may be used to select the proper amount of resection tothe humeral head and, correspondingly, the proper prosthesis to be usedfor that particular resection. It should be appreciated that due to thevariations in the size of the patient and his or her respective humerus,a wide variety of prostheses may be required to accommodate thevariations in a patient's humerus.

[0079] The gauge 10 of FIG. 1 and the gauge 110 of FIG. 8 may be made ofany suitable, durable material that may be sterilized by currentsterilization techniques. For example, the gauge can be made of metal,for example, a stainless steel alloy, a cobalt chromium alloy or atitanium alloy.

[0080] Not only may the selection of a proper prosthesis be governed bythe proper radius of the articulating surface, variations in theprogress of the osteoarthritis may result in the flattening of the headof the humerus being in various stages of progression. Due to thechanges in the progression of the disease and the resulting shape of thehumeral head, the resection plane may vary from being somewhat shallowto being much deeper into the humerus. Therefore, even for a given sizeof the articulating surface of the prepared natural humerus, theposition of the resection, including the planar part of the resection ofthe humerus, may vary. The need to provide for patient variations may beaccomplished by providing a wide variety of sizes and configurations ofthe prosthesis. The availability of a wide variety of sizes andconfigurations of prostheses may be quite costly both in smallmanufacturing lot sizes, as well as in excess inventory. The applicantshave discovered that the prosthesis may be made with more than onecomponent.

[0081] For example, and referring now to FIG. 11, a prosthesis 210 isshown which includes a plurality of components. As shown in FIG. 11, theprosthesis 210 includes in addition to a body 220, a spacer 250. Thespacer 250 provides for a variety of locations of the planar portion 56of the support surface of the long bone or humerus 4 (see FIG. 7). Thus,by utilizing the prosthesis 210, a common body 220 may be used with avariety of spacers 250 having different thicknesses T1. Thus, for anyprosthesis 210 a plurality of planar dimensions PD may be provided bymerely changing the spacer 250 to either a thinner or a thicker spacer.

[0082] For simplicity, the gauge 10 of FIG. 1 and the gauge 110 FIG. 8,may be designed such that the indicia 34, for example the numerals 40,may directly correspond to a particular thickness, part number or otherreference to a particular spacer with the appropriate thickness. Thus,the gauge 10 of FIG. 1 may be used to directly determine the particularspacer to be used for a particular humerus 4.

[0083] As shown in FIG. 11, the prosthesis 210 includes the body 220.The body 220 includes an articulating surface 222 extending in a seconddirection 232 as well as a stem 240 extending in a first direction 230opposed to the second direction 232.

[0084] As shown in FIG. 11, the body 220 includes a body planar surface252 to which the spacer 250 is placed. The spacer 250 defines planarportion 236 of support surface 226 and works in conjunction with arcuatesurface 234 of the body 220 to support the prosthesis 210 against thehumerus wall.

[0085] As shown in FIG. 11, the spacer 250 preferably has a pair ofspaced apart parallel faces defined with thickness T1. The spacer 250has a central opening 254 to permit the spacer 250 to be positioned inplace against the body planar surface 252 with the stem 240 passingthrough the opening 254.

[0086] Preferably, and as shown in FIG. 11, the spacer 250 is secured tothe body 220 by, for example, a connector 256. The connector 256, may,as shown in FIG. 11, be in the form a threadable connection. Forexample, the connector 256 may include external threads 260 located onthe distal portion of the stem 240. The external threads 260 on the stem240 cooperate with matching internal threads 262 on the spacer 250. Afeature, not shown, in the form of, for example, a recess on the planarportion 236 of the spacer 250 may be utilized to secure the spacer 250against the body 220. The body 220 and the spacer 250 may be made of anysuitable durable material that is compatible with the human body. Forexample, the body 220 and the spacer 250 may be made of a durableplastic, a ceramic or a metal. If made of a metal, the body 220 and thespacer 250 may be made of, for example, a cobalt chromium alloy, atitanium alloy, or a stainless alloy.

[0087] Referring now to FIG. 12, an alternate prosthesis for use withthe gauge of the present invention is shown as prosthesis 310.Prosthesis 310 includes a body 320 similar to the body 220 of theprosthesis 210 of FIG. 11 in that the body 320 includes stem 340 similarto stem 240 of FIG. 11. The prosthesis 310 further includes a spacer 350similar to the spacer 250 of the prosthesis 210 of FIG. 11.

[0088] The spacer 350 is secured to the body 320 by means of a connector356. The connector 356 is different than the connector 256 of theprosthesis 210 in that the connector 356 is in the form of a taper fit.The spacer 350 includes a tapered opening 362 that engages with taperedstem portion 360 of the stem 340 of the prosthesis 310. The body 320includes an articulating surface 322 and an opposed arcuate supportsurface 334. The spacer 350 includes a planar support surface 336 which,together with the arcuate support surface .334, form the support surface326 for supporting the prosthesis 310 within the humerus.

[0089] Referring now to FIG. 13, an alternate prosthesis for use withthe gauge of the present invention is shown as prosthesis 410. Theprosthesis 410 of FIG. 13 is similar to the prosthesis 310 of FIG. 12,and includes a body 420 similar to the body 320 of FIG. 12. The body 420includes an articulating surface 422 and an opposed arcuate supportsurface 434. The body 420 in integral with a stem 440 similar to thestem 340 of FIG. 12. The prosthesis 410 further includes a spacer 450similar to the spacer 350 of the prosthesis 310 of FIG. 12.

[0090] The spacer 450 is secured to the body 420 of the prosthesis 410by means of a connector 456 that is different than the connector 356 ofthe prosthesis 310 of FIG. 12. The connector 456 is in the form of aplurality of socket head hex cap screws. The cap screws 456 are fittedinto recessed openings 466 in the spacer 450. The cap screws 456 aresecured to the body 420 by a plurality of threaded openings 468. Thespacer 450 provides planar support surface 436.

[0091] Referring now to FIG. 14, an alternate prosthesis for use withthe gauge of the present invention is shown as prosthesis 510.Prosthesis 510 is similar to the prosthesis 210, 310 and 410 in that theprosthesis 510 includes a body 520, a spacer 550, and a stem 540. Theprosthesis 510 is different than the prosthesis 210, 310 and 410 in thatthe spacer 550 and the stem 540 are integral with each other. The body520 of the prosthesis 510 thus does not include the stem 540 and is aseparate part from the spacer 550 and the stem 540.

[0092] As shown in FIG. 14, the body 520 has a generally hollowhemispherical shape having a articulating surface 522 and an opposedarcuate support surface 534. The spacer 550 has a general disc shapewith the stem 540 having a generally cylindrical shape and extendingoutwardly from the center portion of the spacer 550. The spacer 550 issecured to the body 520 by means of a connector 556.

[0093] The connector 556 as shown in FIG. 14 is in the form of athreaded stem extending from the spacer 550 in a direction opposed tothe stem 540. The connector 556 includes external threads 560 that matewith internal threads 562 in the body 520. The spacer 550 forms planarsupport surface 536 that together with the arcuate support surface 534forms support surface 526 for supporting the prosthesis 510 against thehumerus.

[0094] Referring now to FIG. 15, another embodiment of the presentinvention is shown as prosthesis 610. Prosthesis 610 is similar to theprosthesis 210 of FIG. 11. Prosthesis 610 includes a body 620 similar tothe body 220 of FIG. 11 and includes an articulating surface 622 andopposed arcuate support surface 634. The body 620 includes a stem 640similar to the stem 240 of FIG. 11. The prosthesis 610 further includesa spacer 650 similar to the spacer 250 of FIG. 11. The spacer 650includes a planar support surface 636, which together with the arcuatesupport surface 634 serve to form support surface 626 for supporting theprosthesis 610 against the humerus. The prosthesis 610 further includesa connector 656 similar to the connector 256 of the prosthesis 210 ofFIG. 11.

[0095] Unlike the prosthesis 210, the prosthesis 610 includes a porouscoating 670 located on the planar support surface 636 and the arcuatesupport surface 634. The porous coating 670 serves to provide additionalsurface for promoting bony ingrowth into the prosthesis 610 for improvedfixation of the prosthesis 610 to the bone contour 12.

[0096] Any suitable commercially available porous coating may besuitable for the coating 670. For example, the coating may be in theform of POROCOAT®, a product of the assignee of the instant application.More information regarding the coating may be available by referring toU.S. Pat. No. 3,855,638 to Pilliar, incorporated herein by reference inits entirety.

[0097] Referring now to FIG. 16, an alternate prosthesis for use withthe gauge of the present invention is shown as prosthesis 710.Prosthesis 710 is a three-part prosthesis including a body 720. The body720 includes a hemispherical outer articulating surface 722 and aconcave internal arcuate support surface 734. The prosthesis 710 furtherincludes a plug 750. The plug 750 includes a planar support surface 736and an opposed spherical outer surface 772 which mates with the arcuatesupport surface 734 of the body 720.

[0098] The plug 750 may be secured to the body 720 by any suitablemethod. For example, as shown in FIG. 16, a first connector 756 in theform a taper connection is shown. The first connector 756 includes anexterior taper 760 extending from the plug 750, which mates with aninternal taper 762 in the body 720. The prosthesis 710 further includesa generally cylindrical tapered stem 740, which is secured to the plug750 by a second connector 774.

[0099] The stem 740 may be secured to the plug 750 by, for example, thesecond connector 774. The second connector 774 may have any suitableconfiguration and may, as shown in FIG. 16, be in the form of anexternal taper 776 located on the stem 740, which cooperates with aninternal taper 778 formed in the plug 750.

[0100] As shown in FIG. 16, the prosthesis 710 may further include acoating 770 in the form of, for example, a porous coating, for example,POROCOAT® to encourage ingrowth to assist in the securing of theprosthesis 710 to the bone contour 12. The coating 770 may be secured tothe stem 740, as well as to the arcuate support surface 734, as well asthe planar support surface 736.

[0101] Referring now to FIG. 17, a trial 33 for use with the gauge andsurgical method of the present invention is shown. A trial 33 isutilized during shoulder arthroplasty to verify the proper selection ofthe prosthetic member by implanting the trial 33 into the humeral headand performing trial reductions on the arm to verify the selection ofthe particularly sized trial and corresponding prosthesis. Just as thegauge 10 of FIG. 1 may be utilized to select the proper dimensions formachining the humeral head of the humerus, as well as for selecting theappropriate prosthetic member to be used, the gauge 10 of FIG. 1 may beutilized to select the proper trial for a particular arthroplastysurgery.

[0102] The trial 33 may be removed and replaced with the correspondingprosthesis. The trial 33 may be reused after sterilization. The trial 33may therefore be made of any suitable durable material and may, forexample, be made of a durable plastic that may be sterilized by standardsterilization methods, such as an autoclave.

[0103] The trial 33 mimics the size and shape of the prosthesis. Thetrial 33 therefore includes an articulating surface 35 and an opposedsupport surface 37. The trial 33 further includes a stem 39 extendingoutwardly from the support surface 37. As shown in FIG. 17, the trial 33may also include a plurality of spaced-apart openings 41 to assist inthe removal of the trial 33.

[0104] Referring now to FIG. 18, a kit 70 for use when performing anarthroplasty to implant the prosthesis of the present invention. The kit70 includes a guide pin 61, a guide pin alignment tool 71 for assistingin aligning the guide pin and positioning it into the humerus. Theinstrument kit 70 also includes a cutting tool assembly 72 for preparingthe humeral head. The instrument kit 70 further includes a cutting toolassembly wrench 73 for assembling and disassembling the cutting toolfrom the cutting tool assembly 72. The instrument kit 70 also includesforceps 74 for securely gripping items. The instrument kit 70 alsoincludes a humeral head impactor 75 which may be used with surgicalmallet 76 that drives the implant into its final seat.

[0105] It should be appreciated that the cutting tool assembly 72 of thekit 70 of FIG. 18 may be a generally hemispherical grater type reamer.Such a grater type reamer provides for a generally hemispherical shapeon the humeral head.

[0106] Referring again to FIGS. 5 through 7, the humeral head may have ashape other than a hemispherical shape and may include a planar surfaceas well as a central bore which may be counterbored. It should beappreciated that the planar surface may be provided by a mill endcutter, reamer or saw and it should be appreciated that the counter borecenter opening may be provided by a two-step type reamer or by twoseparate reamers.

[0107] Referring now to FIG. 19, the humeral head configuration found inFIGS. 6 and 7, may be formed in one step by utilizing the cutting toolassembly 72 of FIG. 18 with a combination cutting tool reamer 80 asshown in FIG. 19. Applicants have found that a cutting tool in the formof, for example, a reamer 80 may be provided which simultaneouslyprovides the hemispherical shape, the central opening for the stem ofthe prosthesis, a counter bore, as well as a planar surface.

[0108] This cutting tool 80 includes a hemispherical body 81. Thehemispherical body 81 is hollow, including a plurality of openings 83having cutting edges 84 on the edge of the openings 84 for removing thematerial necessary to form the hemispherical shape on the humerus. Thecutting tool 80 also includes a cylindrical reamer 85 for preparing thehumerus for receiving a stem prosthesis. The cutting tool 80 may alsoinclude a series of circumferential saw teeth 86 located on the outerperiphery of the body 81. Further, the cutting tool or reamer 80 mayinclude a central opening 87 for receiving a guide pin to stabilize thereamer during cutting and assure its proper position.

[0109] Referring now to FIG. 20, an alternate prosthesis for use withthe gauge of the present invention is shown as prosthesis 810.Prosthesis 810 is similar to prosthesis 710 of FIG. 16 and includesthree components, namely a body 820 similar to body 720 of theprosthesis 710 of FIG. 16, a stem 840 similar to the stem 740 of theprosthesis 710 of FIG. 16, and a plug 850.

[0110] The plug 850 is similar to the plug 750 of the prosthesis 710 ofFIG. 16 except that the plug 850 and the stem 840 are secured to thebody 820 in a different fashion from that of the prosthesis 710. Whilethe prosthesis 810 similar to the prosthesis 710 has its componentsinterconnected by means of tapered connections, the tapered connectionsof the prosthesis 810 are different from those of the prosthesis 710 ofFIG. 16.

[0111] For example, the prosthesis 810 includes a first connector 856 inthe form of a tapered connection. The tapered connection 856 includes anexternal taper 860 formed on the stem 840 which connects with aninternal taper 862 formed on the body 820. The plug 850 is secured tothe stem 840 by means of a second tapered connection 874. The secondtapered connection 874 includes an external taper 876 formed on the stem840 which connects with an internal taper 878 formed on the plug 850.The plug 850 includes a support surface 836 that, together with thearcuate surface 834 of the body 820 form support surface 826 of theprosthesis 810 for the securing the prosthesis 810 to the humerus.

[0112] Referring now to FIG. 21, another prosthesis for use with thegauge of the present invention is in the form of a kit and is shown askit 900. The kit 900 includes a body 920 similar to the body 720 of theprosthesis 710 of FIG. 16. The body 920 includes an articulating surface922 and an opposed support surface 934. The kit 900 further includes afirst spacer in the form of a plug 950. The first spacer 950 is similarto the first spacer or plug 750 of the prosthesis 710 of FIG. 16.

[0113] The body 920 and the first spacer 950 combine to form prostheticmember 910. The prosthetic member 910 may further include an optionalstem 940 similar to the stem 740 of FIG. 16. The kit 910 in addition tothe first spacer 950 includes a second spacer 980.

[0114] The second spacer 980 may selectively be included or excludedfrom the prosthetic member 910 such that planar support surface 936 maybe located for example on the first spacer 950 or alternatively on thesecond spacer 980. The kit 900 may optionally further include a thirdspacer 982 or additional spacers not shown. When the kit 900 includesthe body 920, the first spacer 950 and the second spacer 980, the kit900 may be utilized by selectively picking the inclusion ornon-inclusion of the second spacer 980, thereby providing for avariation in the location of the support surface 936.

[0115] The kit 900 permits the use of a prosthesis with a variety oflocations for the support surface 936. The ability to vary the locationof the support surface is important when dealing with diseased humerusin which the flattened head may vary from patient to patient, and thecorresponding required amount of resection may vary for a given geometryof the humerus.

[0116] The prosthetic of kit 900 may be built by utilizing the body 920and the plug 950 as well as a combination of one or the other of thesecond and third spacers 980 or 982, respectively, or by the use of bothspacers 980 and 982. Similarly, the prosthetic member 910 may beperformed without the use of either the second spacer 980 or the thirdspacer 982.

[0117] Preferably, and as shown in FIG. 21, the first spacer 950 issecured to the body 920 by use of a first tapered connection 956. Thefirst tapered connection 956 as shown in FIG. 21, includes an externaltaper 960 formed on the first spacer 950, which mates with an internaltaper 962 formed on the body 920. The second spacer 980 may be securedto the plug 950 by the use of a second tapered connection 974.

[0118] The second tapered connection 974 may include an external taper976 formed on the second spacer 980 which mates with an internal taper978 formed in the first spacer 950. Similarly, the second spacer 980 maybe connected to the third spacer 982 by means of a third taperedconnection 984. Similarly, the third spacer 982 may be connected to thestem 940 by means of a fourth tapered connection 986.

[0119] Preferably, and as shown in FIG. 21, the second taperedconnection 974, the third tapered connection 984 and the fourth taperedconnection 986 are identical to each other so that the stem 940 may beconnected to any of the first spacer 950, second spacer 980 or thirdspacer 982.

[0120] Referring now to FIG. 22, a kit for use in performing jointarthroplasty on a bone according to the present invention is shown askit 102. The kit 102 includes a first gauge 104, including a first gaugebody 106 having a body contact portion 108 for contact with the bone 4.The first gauge 104 further includes a first gauge probe 112 movablypositioned with respect to the body 106. The first gauge probe 112includes a contact portion 114 for contact with the bone 4. The relativeposition of the first gauge probe 112 with respect to the first gaugebody 106 is indicative of the contour of the bone 4.

[0121] The kit 102 further includes a second gauge 116. The second gauge116 includes a second gauge body 118 having a body contact portion 120for contact with the bone 4. The second gauge 116 further includes asecond gauge probe 126 movably positionable with respect to the secondgauge body 118. The second gauge probe 126 includes a probe contactportion 128 for contact with the bone 4. The relative position of thesecond gauge probe 126 with respect to the second gauge body 118 isindicative of the bone contour of the bone 4. The second gauge 116 hasat least one dimension different from that of the first gauge 104.

[0122] While the dimensions that may be different from the first gauge104 to the second gauge 116 may be any dimension, for example, one suchdimension represents the body contact portion 108 of the first gauge 104and the body contact portion 120 of the second gauge 116. It is thecontact portions 108 and 120 that are designed to correspond to aparticular dimension of a prepared humerus and a particular dimension toa corresponding prosthesis to be implanted.

[0123] Thus, for each particular size prepared radius of a humeral head,a particular gauge should be used. For each of those particular gaugesthat should be used, a corresponding prosthesis should be selected. Forexample, as shown in FIG. 22, the body contact portion 108 of the firstgauge 104 is defined by center point 130 from which radius R₁ is used todescribe the locus of points defining the body contact portion 108 ofthe first gauge 104. Similarly, radius R_(s) extending from center point132 of the second gauge 116 defines the locus points defining the bodycontact portion 120 of the second gauge 116. Radius R₁ and radius R_(s)are different and correspond to a particular prepared humeral head and aparticular inner periphery of a implantable prosthesis.

[0124] As shown in FIG. 22, the first gauge 104 and the second gauge 116may include longitudinal openings 134 and 136, respectively. The firstgauge probe 112 may be in the form of a rod that slidingly fits in theopening 134. Similarly, the second gauge probe 126 may be in the form ofa rod that is slidably fitable into the second gauge opening 136.

[0125] As shown in FIG. 22, the first gauge 104 may include indicia 140corresponding to the relative position of the first gauge body 106 tothe first gauge probe 112. Similarly, the second gauge 116 may includeindicia 142 corresponding to the relative position of the second gaugebody 118 to the second gauge probe 126. The first gauge body 106 of thefirst gauge 104 may include a viewing opening 146 for viewing the bone 4and similarly, the second gauge 116 may include a viewing opening 148 inthe second gauge body 118 for viewing the bone 4.

[0126] Referring now to FIG. 23, another embodiment of the presentinvention is shown as kit 150. Kit 150 is similar to kit 102 andincludes first gauge 104, as well as, second gauge 116 of FIG. 22. Thekit 150, however, further includes a first implant 152, including afirst implant surface 156 for contact with the bone. The kit 150 furtherincludes a second implant 158, including a second implant surface 160for contact with the bone. The second implant 158 has at least onedimension different from the corresponding dimension of the firstimplant 152.

[0127] While the implants 152 and 158 may have any suitable shape andmay be unitary or be made from multiple pieces, for example, as shown inFIG. 23, the first implant 152 includes a body 162 and a stem 164extending from the body 162. The first implant 152 further includes aspacer 166 positioned between the stem 164 and the body 162. Similarly,the second implant 158 includes a body 168 and a stem 170 extending fromthe body 168. A spacer 172 is positioned between the body 168 and thestem 170.

[0128] While the kit 150 includes a pair of implants with the pairhaving a different or unique dimension and a pair of gauges with thegauges each having a particular unique dimension, an example ofdifferent dimension for the gauges and the implants as shown in the kit150 of FIG. 23 includes, for example, a body contour portion 108 of thebody 106 of the gauge 104 having a dimension defined by dimension R1_(G) extending from center point 132. The dimension R1 _(G) issignificantly different than the dimension R2 _(G) of the body contourportion 120 of the second gauge 116.

[0129] Further, as shown in FIG. 23, the first implant 152 has a firstimplant surface 156 defined by radius R1 _(I) extending from centerpoint 176. The second implant 158 includes the second implant surface160 defined by radius R2 _(I) extending from center point 178. Thedimension R1 _(I) of the first implant surface 156 is significantlydifferent from the R2 _(I) of the second implant surface 160. As shownin FIG. 23, the body contact portion 108 of the first gauge 104corresponds to the first implant surface 156 of the first implant 152.Similarly, the body contact portion 120 of the second gauge 116corresponds to the second implant surface 160 of the second implant 158.

[0130] Therefore, the first gauge 104 is utilized with the first implant152 and correspondingly, the second gauge 116 is used with the secondimplant 158. In other words, the radius R1 _(G) of the first gauge 104is identical to the radius R1 _(I) of the first implant 152. Similarly,the radius R2 _(G) of the second gauge 116 is identical to the radius R2_(I) of the second implant 158.

[0131] Referring now to FIG. 24, a method 180 for performingarthroplasty is shown. The method includes a first step 182 of providinga gauge for making a measurement of the contour of a long bone. Themethod further includes a second step 184 of making a measurement of thecontour of a long bone with a gauge. The method 180 further includes athird step 186 providing a plurality of joint prostheses. The method 180further includes a fourth step 188 of selecting one of the plurality ofjoint prostheses based upon the measurement of the contour and a fifthstep 190 of resecting a long bone. The method 180 further includes asixth step 192 of implanting the selected one prosthesis onto the longbone.

[0132] According to the present invention and referring now to FIG. 25,another embodiment of the present invention is shown as gauge 1010. Thegauge 1010 is used for measuring femur contour 1012 of the femur 1004for use in hip arthroplasty. The gauge 1010 is similar to the gauge 10of FIG. 1 except the gauge 1010 is designed for use with the femoralhead. The gauge 1010 includes a body 1014 and a probe 1016. The body1014 has a body contact portion 1018 of the body 1014 for contact withthe femur 1004. The probe 1016 is movably positional with respect to thebody 1014. The probe 1016 includes a contact portion 1021 of the probe1016 for contact with the femur 1004. The relative position of the probe1016 with respect to the body 1014 is indicative of the femur contour1012 of the femur 1004.

[0133] The gauge 1010 may, as shown in FIG. 25, be such that at least aportion of the body contact portion 1018 for contact with the femur 1004includes a contoured portion 1020 with a periphery similar to theinternal periphery of the prosthesis to be implanted.

[0134] The gauge 1010 of FIG. 25 may, for example, provide that at leasta portion of the body 1014 includes a concave surface. As shown in FIG.25, the internal periphery 1020 may be concave. In fact, as shown inFIG. 25, the internal periphery 1020 may be hemispherical. While theprobe 1016 may be movably positioned with respect to the body 1014 inany suitable fashion, as shown in FIG. 25, the body 1014 defines alongitudinal opening 1028 therein. As shown in FIG. 25, the probe 1016may be slidably fitted into the opening 1028.

[0135] As shown in FIG. 25, the probe 1016 may include a generallycylindrical portion 1030. The longitudinal opening 1028 may be generallycylindrical.

[0136] The gauge of the present invention may, as shown in FIG. 25,include indicia 1034 located on the body 1014 or the probe 1016. Itshould be appreciated that the indicia 1034 may be located on both theprobe 1016 and the body 1014. The indicia 1034 correspond to therelative position of the probe 1016 with respect to the body 1014. Theindicia 1034 may have any suitable form and may, for example, includemarks 1038 or characters 1040 in the form of, for example, numerals orletters. The marks 1038 and the characters 1040 may be located on eitherthe body 1014 or the probe 1016.

[0137] The alignment of a solitary mark 1038 on the body with thecorresponding mark 1038 on the probe corresponds to the relativeposition of the femur contact surface 1042 of the contact portion 1021of the probe 1016. As shown in FIG. 25, the probe 1016 adjacent thefemur contact surface 1042 may be substantially wider than cylindricalportion 1030 of the probe 1016 in order to obtain a more representativeindication of the femur contour 1012.

[0138] As shown in FIG. 25, the body 1014 of the gauge 1010 may includea viewing opening 1044 for visually sighting the condition of the femurcontour 1012, while positioning the gauge 1010 with respect to the femurcontour 1012. The viewing opening 1044 may have any shape but may, asshown in FIG. 25, be generally elongate and arcuate corresponding to thefemur contour 1012.

[0139] Referring again to FIG. 25, the gauge 1010 may provide anadditional function to that already mentioned by being able to be usedto assist in preparing a locating hole 1046 in the head 1005 of thefemur 1004. The locating hole 1046 may be used to guide tools used toprepare the head 1005 of the femur 1004 for an appropriate prosthesis.When utilizing the gauge 1010 to prepare the locating hole 1046, thebody 1014 of the gauge 1010 is brought in a position relative to thehead 1005 of the femur 1004 by sight as it is located along the femurcontour 1012. Using the viewing window 1044, as well as, the cylindricalportion 1022 of the body 1014 as guides to determine the properorientation of the locating hole 1046. A drill in the form of, forexample, a standard spiral point drill having a size compatible for asliding fit with opening 1028 may be inserted through opening 1028 andused to form the locating hole 1046 after the probe 1016 has beenremoved from the body 1014 of the gauge 1010.

[0140] Although the present invention and its advantages have beendescribed in detail, it should be understood that various changes,substitutions, and alterations can be made therein without departingfrom the spirit and scope of the present invention as defined by theappended claims.

We claim:
 1. A gauge for measuring bone contour of a bone for use injoint arthroplasty, said gauge comprising: a body including a bodycontact portion thereof for contact with the bone; and a probe, movablypositional with respect to said body, said probe including a probecontact portion thereof for contact with the bone, the relative positionof said probe with respect to said body being indicative of the bonecontour of the bone.
 2. The gauge of claim 1, wherein at least a portionof the contact portion of said body comprises a body internal peripherysimilar to a prosthesis internal periphery of a prosthesis to beimplanted.
 3. The gauge of claim 1, wherein at least a portion of thecontact portion of said body comprises a concave surface.
 4. The gaugeof claim 3, wherein said concave surface is hemispherical.
 5. The gaugeof claim 1: wherein said body defines an opening therein; and whereinsaid probe is slidably fitted to the opening.
 6. The gauge of claim 1,wherein at least one of said body and said probe includes indiciathereon corresponding to the relative position of said probe withrespect to said body.
 7. The gauge of claim 1, wherein said body definesan opening for viewing the bone.
 8. The gauge of claim 3: wherein saidprobe defines a longitudinal opening there through; and furthercomprising a rod slidably fitted to the longitudinal opening.
 9. Thegauge of claim 1: wherein the bone is one of a femur and a humerus; andwherein the joint is one of a hip and a shoulder.
 10. A kit for use inselecting one of a plurality of joint implants for use in jointarthroplasty on a bone, said kit comprising: a first gauge, said firstgauge including a first gauge body having a body contact portion thereoffor contact with the bone and a first gauge probe, movably positionalwith respect to the body, the first gauge probe including a probecontact portion thereof for contact with the bone, the relative positionof the first gauge probe with respect to the first gauge body beingindicative of the bone contour of the bone; and a second gauge, saidsecond gauge including a second gauge body having a body contact portionthereof for contact with the bone and a second gauge probe, movablypositional with respect to the second gauge body, the second gauge probeincluding a probe contact portion thereof for contact with the bone, therelative position of the second gauge probe with respect to the secondgauge body being indicative of the bone contour of the bone, said secondgauge having at least one dimension different from that of said firstgauge.
 11. The kit of claim 10, wherein at least one of the body contactportion of the first gauge body and the body contact portion of thesecond gauge body comprises a portion thereof with a contour similar tothe one of the plurality of joint implants to be implanted.
 12. The kitof claim 10, wherein at least one of the body contact portion of thefirst gauge body and the body contact portion of the second gauge bodyincludes a concave surface thereof for contact with the bone.
 13. Thekit of claim 12, wherein the concave surface is hemispherical.
 14. Thekit of claim 10: wherein at least one of the first gauge body and thesecond gauge body defines an opening therein; and wherein at least oneof the first gauge probe and the second gauge probe is slidably fittedto the opening.
 15. The kit of claim 13, wherein at least one of saidfirst gauge and said second gauge includes indicia thereon correspondingto the relative position of at least one of the first gauge body withrespect to the first gauge probe and the second gauge body with respectto the second gauge probe.
 16. The kit of claim 10, wherein at least oneof said first gauge and said second gauge defines an opening for viewingthe bone.
 17. The kit of claim 10: wherein at least one of said firstgauge and said second gauge defines a longitudinal opening therethrough; and wherein said probe comprises a rod slidably fitted to thelongitudinal opening.
 18. The kit of claim 10: wherein the bone is oneof a femur and a humerus; and wherein the joint is one of a hip and ashoulder.
 19. A kit for use in performing joint arthroplasty on a bone,said kit comprising: a first implant including a first implant surfacefor contact with the bone; a second implant including a second implantsurface for contact with the bone, said second implant having at leastone dimension different from the corresponding dimension of said firstimplant; a first gauge, said first gauge including a first gauge bodyhaving a first gauge contact portion thereof for contact with the bone,the first gauge contact portion being shaped to correspond to the firstcontact surface of said first implant; and a second gauge, said secondgauge including a second gauge body having a second gauge contactportion thereof for contact with the bone, the second gauge contactportion being shaped to correspond to the second implant contact surfaceof said second implant, the first gauge contact portion having at leastone dimension which is different from the corresponding dimension of thesecond gauge contact portion.
 20. The kit of claim 19, wherein at leastone of said first gauge and said second gauge includes a body and aprobe, movably positional with respect to the body, the probe includinga portion thereof for contact with the bone, the relative position ofthe probe with respect to the body being indicative of the bone contourof the bone.
 21. The kit of claim 20, wherein the body includes aconcave surface thereof for contact with the bone.
 22. The kit of claim21, wherein the concave surface is hemispherical.
 23. The kit of claim20: wherein the body defines an opening therein; and wherein the probeis slidably fitted to the opening.
 24. The kit of claim 20, wherein atleast one of said first gauge and said second gauge includes indiciathereon corresponding to the relative position of the body with respectto the probe.
 25. The kit of claim 19, wherein at least one of saidfirst gauge and said second gauge defines an opening for viewing thebone.
 26. The kit of claim 19; wherein the bone is one of a femur and ahumerus; and wherein the joint is one of a hip and a shoulder.
 27. Amethod for providing joint arthroplasty comprising: providing a gaugefor making a measurement of the contour of a long bone; making ameasurement of the contour of a long bone with the gauge; providing aplurality of joint prostheses; selecting one of the plurality of jointprostheses based upon the measurement of the contour; resecting a longbone; and implanting the selected one prosthesis onto the long bone. 28.The method of claim 27, wherein the providing the gauge step comprisesproviding a plurality of gauges, each gauge having at least one uniquedimension.
 29. The method of claim 27: wherein the providing the gaugestep comprises providing a gauge which measures voids in the bone; andwherein the providing the plurality of prostheses step comprisesproviding the plurality of prostheses with each prosthesis being adaptedfor a different amount of void in the bone.